no way def not 350 jb3 alone adds maybe 45whp if stock your at 280whp 315 makes sense plus maybe 7 or so for the intake before the heat soak comes in and you loose more so maybe 322 is my guess

I wrote on a good day/high side. ive seen 80WHP gains on JB3 alone. Check out some dynos. Properly done dyno, with proper cooling/fans will yeild good numbers. Most dynos read different and or low, and most dont operate, and have good cooling/fans.
So for a rooftop number he wont be pushing more than 350WHP with that setup is my bet.